Three victims remain at Stroger hospital in serious to critical condition. Fire officials believe arson to be the cause but are still trying to piece together exactly what happened.

Fire spread throughout the 2-flat in the 4200 block of 21st Street but was quickly extinguished. A 33-year old woman police identified as Tamia Johnson died in the fire. Her two children, a 5-year old boy and a 9-year old girl were rushed to the hospital with severe burns covering most of their bodies.

A 35-year old man found outside the building on the front lawn was also burned. He’s also hospitalized. Police are investigating whether he has a role in setting the fire.

Two elderly women who lived upstairs were treated for smoke inhalation.

Fire officials and Chicago police superintendent Garry McCarthy both say the site is now a crime scene. Police are looking into earlier reports that an accelerant, possibly a gasoline can, was found behind the burned out building.